A scientist studying the mosquito-borne encephalitis that has killed seven people in the metro area said yesterday researchers aren’t looking at a new virus, but rather at a new strain of West Nile-like encephalitis.

Dr. Ian Lipkin – part of the team at the University of California at Irvine that is unraveling the identity of the deadly mosquito-borne virus – called the discovery a “big step forward.”

“It looks like a form of the West Nile-like virus that has never before been seen in this hemisphere,” said Lipkin, director of the university’s emerging disease lab.

“It’s definitely a unique form of the West Nile-like encephalitis.”

He vehemently denied a report published yesterday that his team had determined the virus spreading through the New York area was neither St. Louis or West Nile encephalitis, but rather a brand-new virus.

The new West Nile-like strain may be linked to a virus that has sickened people in Russia, he said.

Lipkin and his elite team of virus hunters have completed 20 percent of the genetic profile. Their work is expected to be finished by next month.

City officials initially identified the virus as St. Louis encephalitis. Further tests at the federal Centers for Disease Control and Prevention showed it was the West Nile-like virus.

The city, as of yesterday, had 39 known cases. At least 54 cases have been identified in the entire metropolitan area.

The city’s spraying with the insecticide malathion to kill mosquitoes carrying the West Nile-like virus has been lauded by Lancet, a weekly Bristish medical journal.